JP2005529798A - Vibration-resistant steering wheel and method - Google Patents

Abstract

An automotive steering wheel (10) includes a core member with a circular rim (12). At least one cushioning element (14) having a density greater than that of the core material is mounted in the rim (12), preferably in the channel (11) and preferably substantially around the rim (12). Arranged radially. A method of manufacturing a steering wheel (10) is also provided, the method comprising providing a steering wheel core member (12) having a circular rim cross section (12) with a channel (11), at least one in the channel (11). Placing two cushioning elements (14) and providing a flowable curable material around the rim cross section 12 to secure the cushioning elements therein.

Description

Detailed Description of the Invention

CROSS-REFERENCE TO RELATED APPLICATIONS This application, are incorporated herein by reference, which claims the benefit of the filing date of U.S. Provisional Patent Application No. 60/390076 June 20 Date Application 2002.

TECHNICAL FIELD The present invention relates generally to steering wheels and vehicle steering assemblies, and more specifically to a steering wheel or steering assembly having a high resistance to rotational vibration.

BACKGROUND OF THE INVENTION The long-term goal of automobile designers has been to minimize the vibration of various vehicle systems while driving. The reduction of vibrations results in improved comfort for the driver, with the advantage of increased driving efficiency due to less wear on the car parts and less energy wasted by the vibration elements. Since the structural and functional details of an automobile vary greatly between different vehicle lines and models, the vibration suppression criteria for one vehicle may be different from those of other vehicles. In addition, the vibration characteristics change when new system or structural technologies and even new style designs are introduced into existing vehicle models.

  Of particular interest to designers has been the development of vibration dampeners in vehicle steering wheels. Reducing vibrations transmitted through the steering system reduces driver fatigue and vehicle noise and increases overall driving enjoyment. As a method for reducing the vibration of the steering system, attention is paid to absorbing the vibration transmitted through the steering column using the damper weight, and many methods are known in the art. In one approach, a resilient member is used to connect the airbag module to the steering wheel so that the airbag module acts as a mass damper. However, with this approach, such a system requires a relatively heavy airbag module to effectively suppress rotational vibration. Other systems use a mass damper that is directly associated with the steering column. Such systems are again relatively complex and require a relatively large mass.

SUMMARY OF THE INVENTION In one aspect, a steering wheel for a vehicle is provided. The steering wheel includes a core member having a central mount portion and a plurality of spokes connecting the mount portion to a substantially circular rim. At least one buffering element is fixed to the rim, and the buffering element is made of a material having a density larger than that of the core member, and is fixed to the core member so as to transmit vibration.

  In another aspect, a method for manufacturing a steering wheel is provided. The method includes providing a steering wheel core member having a circular rim cross section with a channel, and disposing at least one cushioning element in the channel having a greater density than the core member. The method further includes the steps of placing the core member and the cushioning element in a molding apparatus and supplying a flowable curable material in the molding apparatus, wherein the cured material adheres to the cushioning element and the core member. The buffer element is fixed to the core member so that vibration can be transmitted.

  In yet another aspect, a steering wheel is provided, the steering wheel including providing a steering wheel core member having a circular rim with a channel, and at least one cushioning element having a greater density than the core member in the channel. And the step of arranging. The method further includes disposing the core member and the cushioning element in a molding apparatus and supplying a flowable curable material in the molding apparatus, the cured material sticking to the cushioning element and the core member. Then, the buffer element is fixed to the core member so as to be able to transmit vibration.

  In yet another aspect, a method for optimizing rotational vibration of a vehicle steering wheel is provided. The method includes forming a steering wheel core member having a substantially circular rim portion connectable to a vehicle steering system, by providing at least one cushioning element and securing it around the rim portion. Attaching the mass to the core member, wherein the cushioning element is preferably disposed substantially radially symmetrical about the core member and has a density greater than the density of the core member.

DETAILED DESCRIPTION Referring to FIGS . 1 and 2, there is shown a partial view of a steering wheel 10 according to a preferred embodiment of the present invention. The steering wheel 10 comprises a core material comprising a substantially circular rim, preferably a metal machined or die-cast rim, and preferably having a circumferential channel 11. The cushioning element 14 is fixed around the rim 12, preferably at least partially disposed within the channel 11 and fixed therein. In a preferred embodiment, the steering wheel core material is die-cast aluminum or magnesium, and is formed as an integral core member having a plurality of spokes (not shown) that connect the rim 12 to a central body (not shown), It is mounted on the vehicle steering system in a conventional manner. When fully assembled, the steering wheel 10 is preferably covered with a known cover material, such as plastic, leather or fiber. When the cushioning element 14, preferably formed of a relatively dense material, is secured to the rim 12, the rotational mass moment of inertia is increased along with the steering moment of inertia to increase resistance to rotational vibration. Here, it is recognized that the actual provision of channels in the rim 12 is not a requirement for the purposes of the present invention, but the channels help to place and hold the cushion weight and are therefore a preferred embodiment. Should. For those skilled in the art, fixing the cushioning material 14 “around” the rim 12 includes a wide variety of fixing means, and it is not necessary to actually attach the cushioning material 14 to the rim 12 itself. You will understand that there is no.

  The channel 11 is preferably substantially U-shaped in cross section, but can be changed accordingly without departing from the scope of the present invention. In a preferred embodiment, the channel 11 is formed when casting an integral core member, but the channel may instead be machined. As an alternative, the entire rim 14 can be manufactured as a separate part and attached to the spokes and central mount portion to assemble the core member. Instead of a U-shaped channel, the rim 12 can be a T-shaped, square, semi-circular, or V-shaped channel, for example. FIG. 3 shows a T-shaped channel 111 mounted in the steering wheel 110. Returning to FIGS. 1 and 2, the cushioning material 14 can also be formed to have a variety of cross-sectional shapes as well, preferably designed to substantially match the cross-section of the channel 11, there The cushioning material 14 is disposed on the surface. In a preferred embodiment, the channel 11 is continuous around the circular rim 12, but the rim 12 has a plurality of channels that are located circumferentially around the rim 12, separated by a filling region. It should be understood that it may be. In one preferred die casting process, the portion of the channel provided with a gate for the supply of molten metal remains filled. The cushioning material 14 is preferably a complete or partial ring made of a material with a higher density than the rim 12, such as lead, steel, tungsten, or other metals. The buffer element (s) can also be a sufficiently dense non-metallic material, such as high density polyvinyl chloride (PVC).

  Various designs are possible, and instead of a ring or partial ring, the cushioning material 14 may include a plurality of parts, preferably arranged substantially symmetrically around the steering wheel 10. The cushioning element is preferably substantially radially symmetric around the rim, although alternative constructions are contemplated where the mass is oriented asymmetrically around the center of the wheel. In yet another embodiment, two partial circular members are used instead of a continuous ring. In this embodiment, two separate members can be placed in the channel 11 to allow the discontinuous buffer structure 14 to accommodate the solid region resulting from the gate in the mold. In the present description, the cushioning material 14 is referred to as a singular, but it should be understood that these descriptions are equally applicable to embodiments using a plurality of cushioning materials. In yet another contemplated embodiment, as shown in FIG. 4, channel 211 fills channel 211 with pressurizable metal powder or metal grinding / turning scrap 214 to hold material therein. Or heated and pressed to form a cushioning member that can be handled similarly to the cushioning member / ring as described above.

  Various different ways of mounting the cushioning material 14 around the rim 12 are conceivable. In a preferred embodiment, the cushioning material 14 is mounted substantially within the channel 11, but depending on the size of the cushioning material and the channel itself, the cushioning material may be entirely or partially within the channel 11. It can also be attached to. Thus, as used herein, the term “inner” is understood to mean being in the channel 11 as a whole and partly. Further, as described above, the use of the channel is not a necessary condition, and the weight-added cushioning member can be fixed on the steering wheel rim by other means. For example, instead of a channel in the rim, the rim itself can be formed with a rounded outer surface that can mate with a channel in the cushioning material. Furthermore, no channel type interface is required at all. The cushioning element may be formed with a flattened side that can be arranged flush with the flattened portion of the rim, for example. The cushioning element can also be attached to the rim by fasteners, adhesives, or spot welding. Various other alternative approaches are possible and those skilled in the art will recognize that a wide variety of differently shaped rims and cushions can be used without departing from the scope of the present invention.

  As used herein, “vibrational communication” is understood to mean that vibration is transmitted between two structures. In a preferred mounting method, the rim 12 (and the core member) including the inserted cushioning material 14 is placed in an injection mold (not shown) with the channel 11 facing upward. Next, a multi-component elastomeric foamable material is fed into the mold in a process called reaction injection molding in the art. The foam material or adhesive is preferably a polyurethane foam or composite known in the art and adheres to the cushioning material 14 and the rim 12 to hold the cushioning material 14 in its desired position, An elastic coating layer is provided outside the wheel. This part is later painted or covered with leather, plastic, etc. to finish the steering wheel. It should be further appreciated that the cushioning material 14 is preferably formed of a material having a melting point sufficient to withstand the temperature during reaction injection molding, which is typically 100. More specifically, it is in the range of 100 ° C to 120 ° C. An illustrative example of a suitable injection molding method is described in US Pat. No. 6,386,063 to Hayashi et al., Which is incorporated herein by reference. Those skilled in the art will appreciate that a wide variety of known adhesives and elastomeric materials can be used as steering wheel cover / buffer material without departing from the scope of the present invention.

  Therefore, although the cushioning material 14 is fixed in the channel by the foam, the flexibility of the flexible foam material can give freedom to the movement of the cushioning material 14. The cushioning material 14 may be mounted in the channel 11 so that the cushioning material piece (s) are in constant contact with the rim 12 and translational and rotational vibrations from the core material are directly transmitted to the cushioning material. it can. As an alternative, a layer of foam or other resilient material can be placed between the cushioning material and the core material to cause the foam to absorb energy before transferring energy to the cushioning material. With such a design, part of the energy of rotational vibration can be absorbed by the expansion and contraction of the foam. Similarly, the use of an elastic foam also increases the resistance to translational vibrations, and the cushioning material can be prevented from non-rotating, that is, linear vibrations due to expansion and contraction of the foam. Other ways of attaching the cushioning material 14 to the core member are also conceivable, such as mechanical fixture (s) such as rivets or screws, or the cushioning material 14 can be fixed in place by bending, There are tabs attached to the rim 12. In embodiments that utilize tabs to hold the cushioning material 14 in place, the tabs can be formed integrally with the rim 12 in a die casting process, or can be attached individually after the rim 12 is formed. Yet another possible method for attaching the cushioning material 14 to the rim 12 is to press fit the cushioning material 14 into the channel 11 or to crimp the rim 12 and secure the cushioning material 14 therein. .

Adding weight around the rim of the steering wheel 10 increases the wheel's mass moment of inertia and increases resistance to rotational vibration of the steering wheel. When mass is added to the outside of the wheel, the rotational inertia of the wheel is larger than when mass is added in the vicinity of the rotation axis (central body) of the wheel. The value of the rotational inertia of a hoop that rotates about the cylindrical axis can be expressed by the following equation, as with the steering wheel rim that rotates about the steering column.
I = MR ²
Here, I is rotational inertia, M is the mass of the rim (ring), and R is the radius of the ring. Although this equation only approximates the result when the instant cushioning material 14 is attached to the steering wheel, those skilled in the art will generally recognize that the rotational inertia is the distance between the mass added position and the rotational axis. You will recognize that it increases with the square. In many steering wheel designs, the actual axis of rotation is not strictly the center of the wheel, but this formula is generally applicable.

  Therefore, when the rotational inertia increases, that is, the force necessary to start or reverse the rotation of the steering wheel increases, the resistance against the rotational vibration of the wheel increases. Since the mass is only added to the rim, where it has the most effective cushioning effect, the total mass that must be added to reduce vibrations can be minimized. By minimizing the required mass, the reduction in the natural frequency of the steering wheel is not as great as in systems that use a relatively large mass added near the center of the wheel, for example. It has been a designer's goal to avoid building a steering wheel system that has a natural frequency encountered in driving the vehicle as a whole, such as the natural frequency of the engine or the natural frequency of the vehicle itself. As will be appreciated, the present invention adds minimal mass while maintaining a steering wheel natural frequency that is different from the vehicle or engine natural frequency, thereby undesired resonance vibration of the steering wheel. Makes it possible to minimize Furthermore, by avoiding the need to add excess mass, it becomes cheaper and can greatly change the collision performance of the steering system and related components, ie, the air bag module, or others close to the wheel's axis of rotation. This reduces the risk of problems that may occur when a relatively large mass is added to the location.

  Problems associated with rotational vibrations involve a phenomenon called “lumpy return” in the art. As the vehicle begins to turn, the subsequent return of the steering wheel to the center position occurs with a series of jerky or bumpy motions rather than the desired smooth motion. By adding mass to the wheel, in particular adding mass externally, changes in the road surface as well as variations in power steering operation reduce the degree to which the smoothness of the return to the center position of the wheel is reduced. Similarly, adding mass to the steering wheel as a whole increases the resistance of the wheel to translational vibrations, ie non-rotational vibrations.

  In a related aspect, the present invention provides an adjustable method for optimizing the rotational vibration of a vehicle steering wheel, for example increasing the resistance thereto. In different vehicle lines, even in vehicles of the same manufacturer and model, the optimal rotational vibration characteristics can change due to subtle differences in components and manufacturing. In a preferred embodiment, cushioning materials having various densities, dimensions, shapes, and weights are available for attachment to the steering wheel 10. Simulation devices well known in the art are used to simulate, for example, flat roads, bumpy roads, and turning conditions encountered by vehicle steering systems. That is, objective measurement values of vibration amplitude and frequency can be recorded under different simulation conditions.

  During testing, a different ring or alternative buffer structure is inserted into the channel 11 to provide the steering system with greater or lesser resistance to rotational vibration and greater or less natural vibration frequency. In this way, individual ring (s) or cushioning materials can be selected that provide suitable vibration characteristics for a particular vehicle. A preferred test procedure involves assembling the steering wheel device without the buffer insert 14 and then mounting the steering device on the simulator and measuring the vibration characteristics under different conditions. The next step, if necessary, is to install the heaviest of the available cushioning materials on the channel 11 and then perform a second series of tests to determine the vibration characteristics of the weighted steering wheel. taking measurement. If so, use this “heavy” cushioning material for the vehicle or series of vehicles. If unsatisfactory, various other cushioning materials are tested for the steering device until the optimum cushioning material (s) is determined.

  A rig tester and method for evaluating the rotational vibration characteristics of a steering wheel is described by Giacomin, J., Shayaa, MS, Dormegnie, E. and Richard, L in 2001, “A Frequency Weighting Curve For The Evaluation Of Steering. Wheel Rotational Vibration ”, the Journal of Sound and Vibration, and can be found on the Internet at www.shef.ac.uk/mecheng/dynam/ra/human.htm. Other methods for determining the appropriate cushioning material to insert into a particular steering wheel are also conceivable, such as actual vehicle driving tests and subjective data obtained from test drivers. For example, instead of using a simulation device, the driver can drive the vehicle under different conditions and the experimenter can select the optimal cushioning material based on the preferences and experiences that the test driver declares. In some cases, the steering system is fully assembled to the vehicle, except for the cushioning material 14. A ring or cushioning design with various weights is held in the steering wheel to perform a driving test, and after the optimal cushioning material is selected, the cushioning material is permanently molded in place.

  This description is to be construed as illustrative only and should not be construed as limiting the scope of the invention in any way. That is, one of ordinary skill in the art appreciates that various modifications can be made to the embodiments disclosed herein without departing from the scope of the invention as defined by the appended claims. Let's go.

1 is a partial cross-sectional view of a steering wheel according to a preferred structural aspect of the present invention. FIG.

FIG. 2 is a partial elevation view of a steering wheel according to a preferred structural aspect of the present invention, similar to FIG. 1.

FIG. 6 is a partial cross-sectional view of a steering wheel according to a second aspect of the preferred structure of the present invention.

FIG. 6 is a partial cross-sectional view of a steering wheel according to a third aspect of the preferred structure of the present invention.

Claims (21)

A core member having a given density and having a substantially circular rim;
At least one buffering element fixed around the rim, and the buffering element is made of a material having a density larger than the density of the core member, and is fixed to the core member so as to transmit vibrations. A steering wheel for automobiles.   The steering wheel according to claim 1, wherein a circular rim defines a channel and a cushioning element is at least partially secured within the channel.   The steering wheel of claim 2, wherein the channel has a substantially U-shaped cross section.   The steering wheel of claim 2, wherein the channel has a substantially T-shaped cross section.   The steering wheel according to claim 1, wherein the cushioning element is a substantially circular ring.   The steering wheel of claim 1, wherein the cushioning element includes a plurality of cushioning elements located substantially radially symmetrical about the rim.   The steering wheel of claim 6, wherein the cushioning element comprises a plurality of metal particles press-fit into a channel defined by the rim.   The steering wheel according to claim 1, wherein the cushioning element is resiliently held by an elastomeric material. Providing a steering wheel core member having a circular rim cross section with a channel;
Disposing at least one cushioning element in the channel having a greater density than the core member;
Placing the core member and the cushioning element in a molding device and supplying a flowable curable material into the molding device, wherein the cured material adheres to the cushioning element and the core member And the manufacturing method of the steering wheel which fixes the said buffer element so that vibration transmission with the said core member is possible.   The method of claim 9, wherein disposing at least one buffer element in the channel comprises disposing a plurality of buffer elements therein.   The method of claim 9, wherein the step of placing at least one cushioning element in the channel places the cushioning element in continuous contact with a core member.   The method according to claim 9, wherein the step of disposing at least one cushioning element in the channel places a resilient material between the cushioning element and the core member.   The method of claim 9, wherein the feeding step injects a multi-component elastomeric material composition into the molding apparatus.   The method of claim 9, wherein the supplying step supplies an elastomeric material that is resilient when cured.   A steering wheel manufactured by the method of claim 9. Forming a steering wheel core member having a substantially circular rim portion connectable to a vehicle steering system, and providing at least one cushioning element and securing it around the rim portion; A method for optimizing rotational vibration in a steering wheel of a vehicle, comprising the step of attaching a mass to a core member, wherein the cushioning element has a higher density than the core member.   The method according to claim 16, wherein the attaching step comprises a metal cushioning element.   The method according to claim 16, characterized in that the step of attaching provides a non-metallic buffer element. The mounting step includes providing a plurality of buffer elements having different masses, selecting a first buffer element having a first mass, and removably fastening the buffer elements in the channel. With
The method of claim 16, further comprising measuring rotational vibration of the core member with the first buffer element fastened therein. Removing the first buffering element from the channel;
Selecting a second cushioning element having a second mass different from the first cushioning element, and measuring rotational vibrations of the core member with the second cushioning element fastened therein 21. The method of claim 20, further comprising:   A steering wheel formed by a method comprising the method of claim 16.

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